Euphorbia caput-medusae (Medusa's head)

Endemic to the Cape region of South Africa, from Namaqualand to Mossel Bay.

Euphorbia caput-medusae is a sprawling, succulent shrub, reaching 1 m across. It has a rosette of narrow, snake-like, spineless but knobbly branches, each 10–30 mm in diameter that arise from a short woody stem (caudex) and which rapidly lose their leaves . The remaining narrow, fleshy leaves and a cluster of inflorescences are carried at the end of the branches. The specialised inflorescences (cyathia) each have a cup-shaped involucre (a whorl of bracts around or beneath the inflorescence) that is 12 mm or more across, with five incurved (bent inwards) lobes and five green shining glands. Each gland is divided into 3–6 white linear or forked processes (outgrowths) which form a fringe around the individual male flowers, each of which has a single stamen, and the single female flower with an elongated pedicel (flower stalk).

Hand-coloured lithograph of Euphorbia caput-medusae by Matilda Smith (1916) in Curtis’s Botanical Magazine (Image: RBG Kew)

The specimen figured in this featured illustration by Matilda Smith was drawn from the garden of La Mortola, Italy, ‘where it flowered in March 1916 - the only difference from the wild plant being in its considerably thicker branches.’

Curtis’s Botanical Magazine (Editor: Martyn Rix) provides an international forum of particular interest to botanists and horticulturists, plant ecologists and those with a special interest in botanical illustration.

Now well over two hundred years old, the Magazine is the longest running botanical periodical featuring colour illustrations of plants. Each four-part volume contains 24 plant portraits reproduced from watercolour originals by leading international botanical artists. Detailed but accessible articles combine horticultural and botanical information, history, conservation and economic uses of the plants described.

Published for the Royal Botanic Gardens, Kew by Wiley-Blackwell Publishing.
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Euphorbia caput-medusae is cultivated as an ornamental, and is a particular favourite of succulent plant enthusiasts.

Medusa's head is grown behind the scenes, in the Tropical Nursery at Kew.

Kew’s Economic Botany Collection includes a sample of the acrid milky juice from Euphorbia caput-medusae that was donated to Kew by the artist Thomas Baines in 1854, and is available to researchers from around the world, by appointment.

Matilda Smith, who painted the image in Curtis’s Botanical Magazine, was a relation of Joseph Dalton Hooker, Director of Kew from 1865-1885. Hooker trained her as a botanical artist by getting her to draw from living specimens as well as to copy drawings from Curtis’s Botanical Magazine. In 1898 she became the first official paid artist at Kew.

Search Kew's databases for more information on this species

JSTOR Plant Science (includes images of Euphorbia caput-medusae)

PlantzAfrica – Euphorbia caput-medusae

Curtis’s Botanical Magazine (Wiley-Blackwell)